The effect of exogenous and endogenous phytohormones on the in vitro development of gametophyte and sporophyte in Asplenium nidus L.

The fern Asplenium nidus L. is in great demand as an ornamental plant. The aim of this work was to investigate the influence of phytohormones in promoting a gametophytic and sporophytic growth in homogenized sporophytes tissue. Exogenous application of 0.5 and 5 mu M N (6)-benzyladenine, 0.05 and 0.5 mu M indole-3-acetic acid (IAA), and 0.3 and 3 mu M gibberellic acid (GA(3)) favoured sporophyte regeneration, whereas gametophyte regeneration took place when plant material was cultured in a hormone-free liquid MS medium. The endogenous contents of the auxin IAA, the cytokinins trans-zeatin, trans-zeatin riboside, dihydrozeatin, dihydrozeatin riboside, isopentenyladenine and isopentenyladenosine, and the gibberellins GA(1), GA(3), GA(4), GA(7), GA(9) and GA(20) in growing gametophytes and sporophytes were evaluated. Similar levels of the auxin and cytokinins and qualitative differences in the gibberellins were found between both generations.